Which means it’s a stark contrast to his March 2013 attempt: that was probably the most dire speech I’ve ever heard from a Lib Dem leader. Back then, Nick took credit for net migration having fallen by a third, even though net migration is, as Vince Cable has repeatedly pointed out, an absurd measure of success. He also came up with the unworkable proposal for security bonds (ie, upfront cash payments) for immigrants from ‘high-risk’ countries entering the UK.

Fast forward 18 months and both have been ditched. The security bond was stopped in its tracks last year when Theresa May adopted a far more draconian version of the idea. And yesterday Nick delivered his first ringing denunciation of the Tories’ obsessions with reducing net migration:

The Conservatives were completely fixated on the net migration target, and, specifically, their pledge to get it down to 10s of 1000s – a Tory rallying cry in opposition. I told David Cameron during the Leader’s debates – and in the early part of Government: ‘you’ll never deliver it’. I made sure it wasn’t in the Coalition Agreement precisely because it’s unrealistic; because it’s based on a fallacy: if a million Brits leave and a million migrants come you get net migration of zero – does that mean you’ve done the job?

Quite why it’s taken Nick four years to make public his concerns is a mystery to me. I’m assured he has always been utterly opposed to the net migration target and has fought tooth-and-nail behind-the-scenes to stop the Home Office sneaking it in as a Government measure when it has only ever been a Tory aspiration.

If that’s the case – and I’ve no reason to doubt it – why did Nick claim credit for the fall in net migration last year? And why did he not add it to the list of 16 Tory measures he highlighted he’d blocked in his 2013 conference speech? It would have been a good line (“I told them No when they demanded a net immigration target which would have hurt our economy”) guaranteed applause.

But better late than never. And the speech deserves some credit. Three specific proposals – proper border checks to clamp down on illegal immigration, ensuring the English language is a requirement of gaining a driving licence and British passport, attracting the brightest and best to come and work and study here – are welcome.

I’m less enamoured of the proposal to toughen up transitional controls for any new countries accepted into EU membership. This concedes too much ground to the migrant-phobes: the UK has massively benefited from the influx of workers from the EU in the last decade. As the economist Jonathan Portes has observed, “new migrants get jobs, contribute to the economy, pay taxes, don’t use many public services, and don’t take jobs from natives. What, exactly, is the problem?” While Nick Clegg was right to attack the last Labour Government’s mismanagement of the process he should also have praised both the policy and its intent. Even if senior Labour figures like Yvette Cooper and Jack Straw won’t stick up for their party’s record on this, liberals should.

However, we are where we are. With the right-wing media and Ukip whipping up absurd fears of 485 million Europeans wishing to descend on the UK we’ve got to the stage where it’s no longer apparently possible simply to state facts and expect them to be listened to. The Daily Express or Nigel Farage can name any figure and some people will believe them; repeat it often enough, as the rest of the media and the Tories do, and their risible claims become hard-to-demolish folk wisdom. In the circumstances, I can understand why Nick Clegg has felt compelled to accept the need to be “stricter and clearer on the transition controls” with any future EU enlargement. He’s wrong to do so, but at least I understand the political imperative — and if that were to be the price of eventual entry for Turkey or Ukraine (should their voters choose to join) then it’s worth paying.

What I don’t yet see from Nick Clegg — and I don’t pretend for a moment it’s an easy task — is a real attempt to turn back the tide of right-wing scaremongering on immigration. Sure, there were lofty appeals to our better instincts yesterday (“this nation is always at its best when we are open and outward-facing”) but there wasn’t enough appeal to our national needs. It’s quite simple: the British economy needs young, productive migrants to counter the effects of our ageing population. Without migrants we will all be poorer.

There are sensible politicians in all parties who understand this — those such as Boris Johnson and Migration Matters, which includes Labour’s Barbara Roche, the Tories’ Nadhim Zahawi as well as the Lib Dems’ Navnit Dholakia. We need to work together, across parties, to win support for humane, liberal policies which offer the country a more prosperous future.

I could, for example, berate Nick Clegg for U-turning on the Lib Dems’ (very sensible) idea of an earned route to citizenship for undocumented migrants. But the plain fact is the policy just isn’t currently acceptable to the public (there are Lib Dems who claim, maybe correctly, that it lost the party half-a-million votes in the last week of the 2010 election). We need to recognise where the public starts on this issue: and that’s a long way from being liberal. What we need to develop is a way of making clear not only why our approach to immigration is fair for all, but also why we’ll all be better off.